I intersected a hand model from maya into my zbrush scene and would like to combine the two subtools into one, and delete the hand on the body mesh. But, i have no clue how to do this 
Could you help me out please? I am using 4.0 btw…
Remesh and Project All could do the trick, if you don’t mind it replacing any existing edgeloops. I don’t think you’ll have to cut off the old hand for this, just smooth/scale it down to a smaller tip and hide it inside the new hand. The tricky part there would be getting a clean result for the fingers as they’re pretty close together. You’ll probably have to use a higher resolution, and/or space them out as much as they can believably get with transpose (you can always transpose them back afterwards).
If you did want to keep your existing edgeloops or have finer control over the result, manual retopology is an option. It would be a much simpler process if you had another program you could GoZ the result over to. If not, the rough steps would be:
- duplicate the two tools, switch to their lowest sub-d levels
- amputate the old hand, I’d cut it off a bit above where the new one would attach
- merge the duplicated tools together
- switch to a zsphere
- Tool:Topology: Select Topo, select the merged mesh
- Tool:Topology: Edit Topology, begin manually connected hand to the arm